What this “Trade Bazooka” involves, gathered from an article on Politico and the Wikipedia article:

Brussels can impose or increase customs duties, restrict exports or imports through quotas or licenses, and impose restrictions on the trade in services.

It also can target the third country’s access to public procurement and foreign direct investment in the EU. Moreover, it can restrict intellectual property rights and access to the bloc’s financial markets.

If those efforts fail, the EU may adopt “response measures” such as tariffs, restrictions on trade in goods and services, limits on access to public programmes and financial markets, or measures affecting intellectual property rights and foreign direct investment.

Methinks this would be about as effective as those 20 Russia sanctions packages the EU has deployed, and in fact, would be playing right into Trump’s hands by further increasing the economic pressure on the EU.

If the EU deployed this “Bazooka”, they would only manage to incinerate themselves in the backblast while only marginally damaging the US.